IPv6 prefix announced, but nothing inside is responding yet. AS213967 announces 2 IPv6 prefix(es) to the global routing table - that’s the part that BGP and our route-server scrape confirm. But our active discovery (curated hostnames, holder-derived domains, authoritative DNS NS/SOA/MX, certificate-transparency hostnames, RIPE Atlas, RDAP, IPv6 Hitlist) found no ICMPv6-responsive host inside the prefix on either vantage, and a yarrp pass against random addresses inside the prefix produced zero in-prefix hops (no router on the path through the AS replied with Time-Exceeded for any random target). That combination usually means the announcement is configured but the addresses inside aren’t in active use yet. The BGP route is there; the operational deployment is still ahead.
AS overview
Test target: 2a05:4144::1 · (no live host found) · address space: unknown · prefixes announced: 2
prefix(es): 2a05:4144::/32, 2a05:4140:35::/48
RPKI & ASPA
2 of 2 prefix(es) covered by a valid ROA.
| Prefix | RPKI state | Reason | Covering VRP(s) |
|---|---|---|---|
2a05:4144::/32 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS213967 /32 maxLen 32 (ripe); AS216164 /32 maxLen 32 (ripe); AS212271 /29 maxLen 48 (ripe) |
2a05:4140:35::/48 | ✓ valid | matched VRP (correct origin, length within maxLength) | AS213967 /48 maxLen 48 (ripe); AS212271 /29 maxLen 48 (ripe) |
ASPA: this AS has published an ASPA record listing 2 upstream provider(s) that are authorized to propagate routes from it: AS49245, AS212271. Routes from this AS that arrive via any other upstream are considered ASPA-invalid by validators that enforce ASPA.
Random-IP probe (yarrp) into the AS' prefixes
We probed 30 arbitrary IPv6 address(es) inside AS213967's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2a05:4140:63::1 at hop 25 - that router answers ICMPv6 Echo. This is not in AS213967's announced prefix; operationally it's the AS-edge / peering interface (often on an IXP peering address or an upstream's /127 link). The traceroute boundary is the AS edge: ICMPv6 Time-Exceeded responses from anything inside this AS are filtered.
ICMPv6 Type 2 (Packet Too Big) acceptance - active test
Type 2 active test inconclusive: no Echo Reply to 1300-byte probe.
method: ICMPv6 Echo + forged PTB, tested 2026-05-25T12:33:18Z
Failure detail — what to grep in your logs
| vantage | our source | your target | method | result | tested (UTC) |
|---|---|---|---|---|---|
| go6lab | 2a00:8642:42::75 | 2a05:4144::1 | icmp6-echo | no_echo | 2026-05-25T12:33:18Z |
| karsolink | 2a12:d8c0:105a:9001::a154 | 2a05:4144::1 | icmp6-echo | no_echo | 2026-05-25T12:41:33Z |
| odin | 2607:fae0:a000::42 | 2a05:4144::1 | icmp6-echo | no_echo | 2026-05-25T12:32:56Z |
Attempt log (go6lab):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 113] No route to hosttls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (karsolink):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 113] No route to hosttls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
Attempt log (odin):
icmp6-echo→ no_echo: no Echo Reply to 1300-byte probedns-tcp→ no_tcp: connect failed: [Errno 113] No route to hosttls→ no_tcp: TLS connect failedhttp→ no_tcp: tcp/80 not open
To match the corresponding ICMPv6 packet on your side (host firewall, AS edge, or transit tap), look for our PTBs around the timestamps above:
sudo tcpdump -i any -n -e 'icmp6 and ip6[40] = 2 and (src host 2607:fae0:a000::42 or src host 2a00:8642:42::75 or src host 2a12:d8c0:105a:9001::a154)'
If you see our PTBs arriving but the destination's TCP/Echo flow does not shrink, the drop is in the destination kernel (cause 3 below). If you don't see them at all, drop is upstream of you (cause 2). If you only see them from one of our two source IPs, the drop is path-asymmetric — one transit on the asymmetric route is filtering, the other is not.
From NL host (go6lab) transit only unreachable
filter likely at: past AS212271 (C1V) · min PMTU on path: 1500
0/4
Echo small (56B) -
0/4
Echo 1500B (DF) -
no
Type 1 dest-unreach
-
TCP responds on
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | 2a00:8642:42::3 | 1.7ms | 0% | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 2 | gw.friends.steffann.nl 2a00:8642:1000:f000::1 | 1.9ms | 0%* | AS203993 | STEFFANN-DC-AS - S.J.M. Steffann, NL |
| 3 | 2a00:1ca8:1::194 | 5.2ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 4 | 2a03:3f40::10:33 | 5.5ms | 0% | AS50673 | Serverius-as - Serverius Holding B.V., NL |
| 5 | 2001:7f8:1:0:4e5e:cff:fe13:cbfa | 31.6ms | 0% | - | NA |
| 6 | 2a01:9a80:0:2f::f | 35.6ms | 0% | AS39120 | CONVERGENZE-AS - Convergenze S.p.A., IT |
| 7 | 2a05:4140:2::2 | 33.2ms | 10% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 8 | dns1.c1vhosting.it 2a05:4140:3::30 | 35.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 9 | 2a05:4140:63::1 | 32.4ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 10 | dns1.c1vhosting.it 2a05:4140:3::30 | 33.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 11 | 2a05:4140:63::1 | 35.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 12 | dns1.c1vhosting.it 2a05:4140:3::30 | 33.2ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 13 | 2a05:4140:63::1 | 36.2ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 14 | dns1.c1vhosting.it 2a05:4140:3::30 | 33.4ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 15 | 2a05:4140:63::1 | 33.7ms | 10% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 16 | dns1.c1vhosting.it 2a05:4140:3::30 | 35.1ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 17 | 2a05:4140:63::1 | 33.5ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 18 | dns1.c1vhosting.it 2a05:4140:3::30 | 32.7ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 19 | 2a05:4140:63::1 | 35.9ms | 30% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 20 | dns1.c1vhosting.it 2a05:4140:3::30 | 34.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 21 | 2a05:4140:63::1 | 33.2ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 22 | dns1.c1vhosting.it 2a05:4140:3::30 | 35.3ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 23 | 2a05:4140:63::1 | 35.2ms | 10% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 24 | dns1.c1vhosting.it 2a05:4140:3::30 | 33.5ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
Rate-limited ICMPv6: hop 7, hop 15, hop 19, hop 23 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.032ms pmtu 1500
1: 2a00:8642:42::3 1.489ms
1: 2a00:8642:42::3 1.359ms
2: no reply
3: 2a00:1ca8:1::194 3.299ms
4: 2a03:3f40::10:33 6.045ms
5: 2001:7f8:1:0:4e5e:cff:fe13:cbfa 33.791ms
6: 2a01:9a80:0:2f::f 33.240ms
7: 2a05:4140:2::2 34.050ms
8: dns1.c1vhosting.it 35.268ms
9: 2a05:4140:63::1 33.280ms asymm 7
10: dns1.c1vhosting.it 33.376ms asymm 8
11: 2a05:4140:63::1 36.166ms asymm 7
12: dns1.c1vhosting.it 37.277ms asymm 8
13: 2a05:4140:63::1 36.704ms asymm 7
14: dns1.c1vhosting.it 36.474ms asymm 8
15: 2a05:4140:63::1 32.850ms asymm 7
16: dns1.c1vhosting.it 35.946ms asymm 8
17: 2a05:4140:63::1 32.936ms asymm 7
18: dns1.c1vhosting.it 37.050ms asymm 8
19: 2a05:4140:63::1 35.642ms asymm 7
20: dns1.c1vhosting.it 35.927ms asymm 8
21: 2a05:4140:63::1 33.776ms asymm 7
22: dns1.c1vhosting.it 36.481ms asymm 8
23: 2a05:4140:63::1 34.160ms asymm 7
24: dns1.c1vhosting.it 34.340ms asymm 8
Too many hops: pmtu 1500
Resume: pmtu 1500 From ITA host (Karsolink) transit only unreachable
filter likely at: past AS212271 (C1V) · min PMTU on path: 1500
0/4
Echo small (56B) -
0/4
Echo 1500B (DF) -
no
Type 1 dest-unreach
-
TCP responds on
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | karsolink-01.net.karsolink.com 2a12:d8c0:105a:9001::1 | 0.4ms | 0%* | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 2 | * | - | 0%* | - | |
| 3 | 2a12:d8c0:101f:6::1 | 10.0ms | 10% | AS204471 | KARSOLINK - 2S Computers SRL, IT |
| 4 | convergenze.minap.it 2001:7f8:c5::a503:9120:1 | 10.1ms | 0% | AS39120 | Convergenze S.p.A. |
| 5 | 2a01:9a80:0:19::1 | 19.4ms | 0% | AS39120 | CONVERGENZE-AS - Convergenze S.p.A., IT |
| 6 | 2a01:9a80:0:2f::f | 19.4ms | 0% | AS39120 | CONVERGENZE-AS - Convergenze S.p.A., IT |
| 7 | 2a05:4140:2::2 | 19.8ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 8 | dns1.c1vhosting.it 2a05:4140:3::30 | 19.8ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 9 | 2a05:4140:63::1 | 19.8ms | 10% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 10 | dns1.c1vhosting.it 2a05:4140:3::30 | 20.2ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 11 | 2a05:4140:63::1 | 20.1ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 12 | dns1.c1vhosting.it 2a05:4140:3::30 | 20.1ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 13 | * | - | 0% | - | |
| 14 | * | - | 0% | - | |
| 15 | * | - | 0% | - | |
| 16 | dns1.c1vhosting.it 2a05:4140:3::30 | 20.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 17 | * | - | 0% | - | |
| 18 | * | - | 0% | - | |
| 19 | 2a05:4140:63::1 | 20.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 20 | dns1.c1vhosting.it 2a05:4140:3::30 | 20.2ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 21 | 2a05:4140:63::1 | 20.2ms | 30% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 22 | dns1.c1vhosting.it 2a05:4140:3::30 | 20.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 23 | 2a05:4140:63::1 | 20.2ms | 20% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 24 | dns1.c1vhosting.it 2a05:4140:3::30 | 19.9ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
Rate-limited ICMPv6: hop 3, hop 9, hop 21, hop 23 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.028ms pmtu 1500
1: karsolink-01.net.karsolink.com 0.759ms
1: no reply
2: no reply
3: 2a12:d8c0:101f:6::1 10.575ms
4: convergenze.minap.it 10.403ms
5: 2a01:9a80:0:19::1 19.902ms
6: 2a01:9a80:0:2f::f 20.117ms asymm 5
7: 2a05:4140:2::2 20.441ms asymm 6
8: dns1.c1vhosting.it 20.665ms asymm 7
9: 2a05:4140:63::1 20.759ms asymm 6
10: dns1.c1vhosting.it 20.997ms asymm 7
11: 2a05:4140:63::1 20.743ms asymm 6
12: dns1.c1vhosting.it 20.710ms asymm 7
13: 2a05:4140:63::1 20.695ms asymm 6
14: dns1.c1vhosting.it 20.565ms asymm 7
15: 2a05:4140:63::1 20.533ms asymm 6
16: dns1.c1vhosting.it 21.421ms asymm 7
17: 2a05:4140:63::1 20.674ms asymm 6
18: dns1.c1vhosting.it 20.786ms asymm 7
19: 2a05:4140:63::1 21.139ms asymm 6
20: dns1.c1vhosting.it 29.448ms asymm 7
21: 2a05:4140:63::1 20.525ms asymm 6
22: dns1.c1vhosting.it 20.586ms asymm 7
23: 2a05:4140:63::1 20.959ms asymm 6
24: dns1.c1vhosting.it 21.042ms asymm 7
Too many hops: pmtu 1500
Resume: pmtu 1500 From SLO host (6connect) transit only unreachable
filter likely at: past AS212271 (C1V) · min PMTU on path: 1500
0/4
Echo small (56B) -
0/4
Echo 1500B (DF) -
no
Type 1 dest-unreach
-
TCP responds on
Path (traceroute + mtr + PTR)
| # | IP / PTR | RTT | mtr loss | AS | AS holder |
|---|---|---|---|---|---|
| 1 | fw1-lju.6connect.com 2607:fae0:a000::2 | 0.3ms | 0%* | AS8038 | 6CONNECT - 6connect, Inc., US |
| 2 | * | - | - | - | |
| 3 | * | - | 0% | - | |
| 4 | 2a00:ee0:1:10::2 | 1.1ms | 0% | AS5603 | SIOL-NET - Telekom Slovenije, d.d., SI |
| 5 | de-cix.convergenze.it 2001:7f8::98d0:0:1 | 30.3ms | 0% | - | NA |
| 6 | 2a01:9a80:0:2f::f | 30.4ms | 0% | AS39120 | CONVERGENZE-AS - Convergenze S.p.A., IT |
| 7 | 2a05:4140:2::2 | 28.5ms | 20% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 8 | dns1.c1vhosting.it 2a05:4140:3::30 | 27.8ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 9 | 2a05:4140:63::1 | 27.8ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 10 | dns1.c1vhosting.it 2a05:4140:3::30 | 27.8ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 11 | 2a05:4140:63::1 | 28.7ms | 70% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 12 | dns1.c1vhosting.it 2a05:4140:3::30 | 28.7ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 13 | 2a05:4140:63::1 | 28.9ms | 30% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 14 | dns1.c1vhosting.it 2a05:4140:3::30 | 28.6ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 15 | 2a05:4140:63::1 | 27.9ms | 60% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 16 | dns1.c1vhosting.it 2a05:4140:3::30 | 27.8ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 17 | 2a05:4140:63::1 | 28.7ms | 70% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 18 | dns1.c1vhosting.it 2a05:4140:3::30 | 28.7ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 19 | 2a05:4140:63::1 | 27.9ms | 30% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 20 | dns1.c1vhosting.it 2a05:4140:3::30 | 28.9ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 21 | 2a05:4140:63::1 | 28.0ms | 60% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 22 | dns1.c1vhosting.it 2a05:4140:3::30 | 27.9ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 23 | 2a05:4140:63::1 | 28.1ms | 90% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
| 24 | dns1.c1vhosting.it 2a05:4140:3::30 | 29.0ms | 0% | AS212271 | C1V - Cinzia Tocci trading as Lumanex Srl, IT |
Rate-limited ICMPv6: hop 7, hop 11, hop 13, hop 15, hop 17, hop 19, hop 21, hop 23 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).
tracepath -6
1?: [LOCALHOST] 0.030ms pmtu 1500
1: fw1-lju.6connect.com 0.588ms
1: fw1-lju.6connect.com 0.494ms
2: ccr-to-fw-ccr1-gw-lju.6connect.com 0.738ms
3: 2a00:ee1:800:9::1 2.123ms
4: 2a00:ee0:1:10::2 1.332ms asymm 3
5: de-cix.convergenze.it 31.358ms asymm 10
6: 2a01:9a80:0:2f::f 30.623ms asymm 11
7: 2a05:4140:2::2 29.426ms asymm 11
8: dns1.c1vhosting.it 27.957ms asymm 11
9: 2a05:4140:63::1 28.737ms asymm 10
10: dns1.c1vhosting.it 28.554ms asymm 11
11: 2a05:4140:63::1 28.267ms asymm 10
12: dns1.c1vhosting.it 28.463ms asymm 11
13: 2a05:4140:63::1 29.171ms asymm 10
14: dns1.c1vhosting.it 28.023ms asymm 11
15: 2a05:4140:63::1 28.220ms asymm 10
16: dns1.c1vhosting.it 28.111ms asymm 11
17: 2a05:4140:63::1 28.364ms asymm 10
18: dns1.c1vhosting.it 28.553ms asymm 11
19: 2a05:4140:63::1 29.135ms asymm 10
20: dns1.c1vhosting.it 28.403ms asymm 11
21: 2a05:4140:63::1 28.451ms asymm 10
22: dns1.c1vhosting.it 29.612ms asymm 11
23: 2a05:4140:63::1 28.927ms asymm 10
24: dns1.c1vhosting.it 28.475ms asymm 11
Too many hops: pmtu 1500
Resume: pmtu 1500